Fujitsu Corporation

Toshihiro Yamanaka

Takehiko Fujiyama

Kenzo Kobayashi

Yoshiyuki Wada

Yuichi Terui

Tetsuya Yasui

Kenji Rikimaru

Mitunori Ono

An apparatus for reproducing a system clock provided with a reproducing unit for reproducing a first time reference clock T , a generating unit for generating a system clock Sck, a generating unit for generating a second time reference clock T , a synchronization control unit for minimizing, based on the clocks T and T , the deviation between these clocks, a first calculating unit for calculating a difference between counts of the clock T counted in a predetermined time interval, and a second calculating unit for calculating a difference between counts of the clock T counted in a predetermined time interval, the outputs of the calculation of the differences being input to the synchronization control unit to minimize the deviation between the clocks, whereby it becomes possible to reproduce high quality data even when switching channels from one node to another node when reproducing digital data from a plurality of sending side nodes at a receiving side node.

Method and apparatus for reproducing system clock in digital data transmission network

A plurality of image transmitting apparatuses are connected to the image transmitting side of a transmission line, a plurality of image receiving apparatuses are connected to the image receiving side of the transmission line, and a plurality of logical channels are set on the transmission line. A predetermined logical channel is fixedly allotted to each image receiving apparatus, and each image transmitting apparatus is provided with a function of transmitting an image to an image receiving apparatus through any logical channel. Each image transmitting apparatus transmits an image to a designated image receiving apparatus through a predetermined logical channel.

Image transmission method and image transmission system

A clock information transmitting device coupled to a digital processing circuit which receives a transmission signal and generates a coded transmission signal includes a PLL circuit for generating a first signal and a sampling clock signal, both being synchronized with a synchronizing signal in the transmission signal. The sampling clock signal is used in the digital processing circuit. A clock information generating part counts pulses of a transmission clock signal and generates clock information indicating a number of pulses of a transmission clock signal in response to one of the synchronizing signal and the first signal generated by the PLL circuit. A multiplexer outputs a multiplexed signal including the clock information and the coded transmission signal to a transmission path.

Clock information transmitting device and clock information receiving

A transmission system is provided having a sender side apparatus, a receiver side apparatus, and a transmission line connecting the sender and receiver side apparatuses. The sender side apparatus provides a selector for receiving image data signals of a plurality of channels in parallel and, frame by frame, selects an image data signal of one of the plurality of channels for each frame. The selector discards the image data signals of the other of the plurality of channels. A coding unit codes the image data signal which is selected for each frame by the selector, by interframe difference coding. A monitoring unit monitor data amounts of interframe differences in the image data signals of the respective channels. A control unit determines which one of said plurality of channels is to be selected by the selector, based on the data amounts of interframe differences in the image data signals of the respective channels, and adaptively controls the selector in accordance with this determination. Channel information is generated indicating the above one of the channels determined by the control unit for each frame. Frame by frame, the image data signal coded by the above coding means is transmitted, together with the above channel information corresponding to the coded image data signal. The receiver side apparatus receives the transmitted image data signal, together with the channel information, and a unit for decodes the received image data signal for each frame.

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Fukuoka, Japan

Toshihiro Yamanaka